Montmorillonite-K10 Catalyzed Addition OF Trimethylsilylcyanide (TMSCN) to Aldehydes

Synthesis and evaluation of highly selective quinazoline-2,4-dione ligands for sphingosine-1-phosphate receptor 2

A series of twenty-nine new quinazoline-2,4-dione compounds were synthesized and their IC50 values for binding toward sphingosine-1-phosphate receptor 2 (S1PR2) were determined using a [32P]S1P binding assay. Seven compounds 2a, 2g, 2h, 2i, 2j, 2k, and 5h exhibit high S1PR2 binding potencies (IC50 values < 50 nM) and four of these new compounds 2g, 2i, 2j, and 2k have IC50 values (<10 nM) of 6.3, 5.7, 4.8, and 2.6 nM, and are highly selective for S1PR2 over other S1PR subtypes, S1PR1, 3, 4, and 5. Compounds 2a and 2i were chosen for C-11 radiosynthesis through O-[11C]methylation of precursors 13 and 2k with good radiochemical yields (35-40%), high chemical and radiochemical purity (>98%), and high molar activity (153-222 GBq μmol-1, at the end of bombardment). [11C]2a and [11C]2i were further evaluated by the ex vivo biodistribution study. The results showed that both tracers have low brain uptake, preventing their potential for neuroimaging application. Further explorations of this class of S1PR2 PET tracers in peripheral tissue diseases are underway.

Catalytic asymmetric cyanosilylation of ketones by a chiral amino acid salt

In this Communication, we describe the first highly enantioselective cyanosilylation of ketones catalyzed by simple chiral amino acid salt. A broad range of aromatic, alpha,beta-unsaturated, heterocyclic ketones catalyzed by l-phenylglycine sodium salt gave the corresponding trimethylsilyl ethers of cyanohydrins in 75-96% yields with 86-97% enantioselectivities. A catalytic cycle based on experimental phenomena and studies has been proposed to explain the origin of this activation. The reaction employed commercially available and fully recyclable catalysts and involves a simple experimental procedure.